Straight-edge for circular saws.



No. 838,551. PATENTBD DEG. 18,1906.

B. LAFLEUH.

STRAIGHT. BDGB FOR CIRCULAR SAWS.

APPLICATION nun AUG.4, 190a.

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UNITED STATES PATENT OFFICE.

STRAIGHT-EDGE FOR-CIRCULAR SAWS.

Specification of Letters Patent.

Patented Dec. 18, 1906.

Application filed August 4, 1906. Serial No. 329,250.

To aZZ whom it may concern:

Be it known that I, BARTHELPJMY LAFLEUR, a citizen of the United States, residing at Elkmouth, in the Province of British Columbia and Dominion of Canada, have invented a new and useful Straight-Edge for Circular Saws, of which the following is a specification.

This invention relates to a tension straightedge for circular or band saws; and it relates more particularly to means whereby the straight edge proper may be flexed or crowned at any desired point.

One of the objects of the invention is to improve and simplify the construction and operation of this class of devices, so that the straight-edge can be adjusted with facility.

A further object is to provide reinforcing or backing members for the straight-edge, which permit of the latter being crowned without danger of buckling.

Another object is the employment of adjusting means in connection with the said members for enabling the straight-edge proper to be crowned at any desired point, either at the center or the ends or midway between the center and'ends.

With these objects in view and others, as will appear as the nature of the invention is better understood, the invention comprises the various novel features of construction and arrangement of parts, which will be more fully described hereinafter and set forth with particularity in the appended claims.

In the accom anying drawings, which illustrate one of t e embodiments of the invention, Figure 1 is a sectional view of a circular saw, showing the apparatus in elevation applied thereto for gaging the crown or tension of the saw. Fig. 2 is a plan view thereof. Fig. 3 is a transverse section of the apparatus.

orresponding parts in the several figures are indicated throughout by similar characters of reference.

Referring to the drawings, 1 designates the blade of the device, which is preferably made of steel of suitable gage and capable of being bowed or crowned. The blade may be of any desired length, and along the back edge or portion thereof are arranged a plurality of independent reinforcing or backing members 2, spaced slightly apart at their end from each other and to each of which the blade is pivotally riveted, as at 3. Each of the mem ers 2 is grooved longitudinally, so as to form jaws 4, that embrace the sides of the blade to prevent buckling or warping when the same is crowned.

Arranged parallel with and at one side of the blade is a stiff bar 5, of steel or other material, that is of approximately the same length as the blade and provided with a plurality of openings 6, spaced. apart over the centers of the reinforcing member 2. Bigidly secured to each of the reinforcing members 2 and disposed at right angles to the general length of the blade is a threaded rod or screw 7, that passes through the opening 6 of the bar in line with the adjacent reinforcing member. The threads 8 of the rods extend a suitable distance above and below the bar, and winged clamping-nuts 9 and 10, respectively, engage the thread on opposite sides of the bar 5 and bear against the latter. Since the blade is riveted to each of the members 2, the manipulation of the clampingnuts will impart longitudinal movement to their respective threaded rod, so that the blade can be set and held to produce any desired contour. It is to be noted that a single rivet is employed for connecting the blade with each of the backing members 2, and the j aws of the backing members do not frictionally grip the blade, but merely embrace the same, so as to prevent buckling. It will thus be seen that the blade can be crowned into a smooth unbroken curve without the reinforcing members interfering, and the clampingnuts will positively hold the blade set.

In order to insure the holding of the blade perpendicular to the saw, a square 11 is employed. The square is arranged at about the middle of the bar 5, with its short arm extending through a transverse opening 12 therein and adjustably held by the clamping-nuts 13. The square is disposed in a position at right angles to the bar, and the long arm is adapted to rest at its end on the saw, as shown, thereby enabling the operator to hold the blade perpendicular to the general plane of the saw.

In practice the apparatus is used in the process of hammering of saws to give them the required tension for different occasions or work and enables the workman to determine with accuracy when the proper tension is obtained. With the straight-edge he can ascertain whether or not a saw is crowned enough or has the proper tension. By crowning the blade of the straight-edge or pulling up the ends with the aid of the thumbnuts the llower edge of the blade "will be slightly rounded, so that the workman hammering the saw can ascertain whether the saw needs to be hammered near the heart or at any other part. serves to hold the apparatus in such a position that the blade will be perpendicular to the saw, and when the saw is hammered to the proper shape the blade will contact with the saw, so that no light will be seen between them.

From the foregoing description, taken in connection. with the accompanying drawings, the advantages of the construction and of the method of operation will be readily appreciated by.,.those skilled in the art to which the invention appertains.

I have described the principle of operation of the invention, together with the apparatus which I now consider to be the best embodiment thereof; but I desire to have it understood that the apparatus shown is merely illustrative and that various changes may be made whendesired as are within the scope of the invention.

Vvhat is claimed is 1. A device of the class described comprising a fiat resilient blade, a plurality of spaced backing members for preventing the blade from buckling, each member being provided with a longitudinal groove for fitting over the blade along one edge thereof, a rivet for each member which extends through the latter and blade, a stiff bar having openings arranged in line with the said members, rods rigidly attached one to each member and extending loosely through the openings of the The square attachment bars, threads on theirodsjfextending to opposite sides of the bar, and nuts on the threaded portions of the rods adapted to engage on opposite sides of the bar.

2, A device of the class described comprising a flat resilient blade, a plurality of spaced backing members for preventing the blade from buckling each member comprising a longitudinally-slotted body for receiving one edge of the blade, a central rivet passing through each body and the blade, a stiff structure having openings extending transversely to the general length of the blade and in line with the said members, a plurality of rods each having a threaded engagement with its respective member at a point in line with the rivet of the member, threads on the rods where they extend through the openings of the structure, and adjusting-nuts engaging the threads.

3. A device of the class described comprising a resilient blade, an unbending member arranged at one side of the blade, a plurality of means arranged to crown the blade and hold it under tension on the member, and a square having one arm adjustably connected with the member and the other arm arranged to hear at its free end on the saw to be gaged for holding the blade vertical on the latter.

In testimony that I claim the foregoing as my own I have hereto aflixed my signature in the presence of two witnesses.

BARTHELEMY LAFLEUR.

Witnesses:

JOHN MoIvoR, JOSEPH SAvARIA. 

